The present invention relates generally to the field of oscillators and more particularly to the field of oscillators that have the capability of producing outputs at multiple frequencies and to oscillators that produce outputs at widely separated frequencies.
Many microwave systems such as wideband receivers require oscillators which provide power at several widely separated frequencies. When these frequencies are separated by more than the tuning range of a single oscillator then several oscillators must be used and a means must be provided for connecting these oscillators to a single output port. In the past this has been accomplished through the use of switches, power dividers and multiplexers. Use of these devices increases the size and complexity of the system and frequently produces undesirable electrical characteristics. Mechanical switches have the disadvantage that they limit the maximum speed with which frequencies can be changed and solid state switches do not have adequate bandwidth, particularly at millimeter wave frequencies. Power dividers introduce undesirable power loss and require the use of oscillators with greater output in order to overcome these losses.